Cook the pasta to al dente, or to the tooth. Follow the package instructions for proper cook times depending on your theof pasta.
In a large saute pan, melt butter. Whisk in flour until thickened, and continue to whisk sporadically for about 2 minutes.
Slowly add whole milk, constantly whisking as you add about 1/2 up at a time. Keep whisking to promote a smooth consistency. Season with salt and grated nutmeg. Start with a little at a time, and then add more later after you add the cheese!
Remove the pan from the heat - you don't want it over heat as you add the cheese, as this can cause the sauce to seize up and get grainy. Add the grated cheese a little at a time, continuing to whisk as it melts. When all the cheese is added, move the pan back to the heat, continuing to whisk.
Taste the sauce and add more salt and nutmeg to your liking. Add sauce to the pasta, a little at a time, until desired consistency is met. Note that you may have extra sauce! You can choose to save the sauce or make more pasta!
Garnish with grated nutmeg and enjoy warm!